Impactor and stabilizer for fracturing calcifications in heart valves

ABSTRACT

A device for fracturing calcifications in heart valves includes a stabilizer and an impactor movable towards each other. The impactor includes one or more impactor arms, each of which extends distally from a proximal cap. The impactor further includes one or more lever arms each of which is distally coupled to a lever cap and proximally coupled to a corresponding one of the one or more impactor arms. The lever cap slides on a shaft which extends towards the proximal cap. Proximal movement of the lever cap towards the proximal cap causes the one or more lever arms to deform and to push against the one or more impactor arms and to cause the one or more impactor arms to deform.

PCT Patent Applications PCT/US2010/058810 and PCT/US2012/067812,assigned to the present assignee, describe devices for fracturingcalcifications in heart valves. The device includes a catheter that hasan expandable stabilizer, an impactor shaft and an internal shaft, alldisposed in an external shaft. Expandable impactor arms are mounted onthe impactor shaft. The internal shaft is movable to cause the impactorarms to expand outwards and be locked in an expanded shape. An impactingelement is movable to cause the impactor arms, while in the expandedshape, to move towards the tissue with sufficient energy so as tofracture a calcification located in tissue which is fixed by thestabilizer in a certain position vis-à-vis the impactor arms. Theinternal shaft may be lockable relative to the impactor shaft so thatthe impactor arms are fixed.

FIELD OF THE INVENTION

The present invention generally relates to devices and methods forfracturing calcifications in heart valves, such as aortic valveleaflets.

BACKGROUND OF THE INVENTION

A brief description of using these prior art devices is as follows. Thecatheter may be delivered over a guide-wire through a blood vessel, suchas the peripheral artery, using a retrograde approach, through theaortic arch and into the ascending aorta, just above the aortic valve.The external shaft is retracted so that the expandable stabilizerexpands and opens up. The stabilizer is used to guide, position andanchor the catheter distal part in the sinuses, just above the valveleaflets. An impactor shaft, including folded impactor arms, is thenpushed forward (distally) through the center of the valve into the leftventricle. When pushed forward the impactor arms are folded so that theycan easily cross the valve. The internal shaft is then pulled proximallyto cause the impactor arms to open (expand) outwards sideways and lockthem in the expanded shape. The impactor and internal shafts aremanipulated so that the leaflets are “sandwiched” between the stabilizer(which may make contact with the leaflets from the aortic aspect) andthe impactor arms (which may make contact with the leaflets from theventricular aspect, or vice versa). In order to fracture leafletcalcifications, the impactor arms are pulled abruptly towards theleaflet tissue to impact the calcification, with the stabilizer servingas an anvil.

SUMMARY OF THE INVENTION

The present invention seeks to provide further impactor devices that maybe used for fracturing calcifications in aortic valve leaflets, in orderto increase leaflet pliability and mobility, either as standalonetreatment, bridge treatment or preparation of the “landing zone” fortrans-catheter valve implantation.

The term “fracture” refers to any kind of reduction in size or anymodification in shape or form, such as but not limited to, fracturing,pulverizing, breaking, grinding, chopping and the like.

There is provided in accordance with an embodiment of the invention adevice for fracturing calcifications in heart valves including astabilizer and an impactor movable towards each other, such as but notnecessarily, on a guidewire, the impactor including one or more impactorarms, each of which extends distally from a proximal cap, the impactorfurther including one or more lever arms each of which is distallycoupled to a lever cap and proximally coupled to a corresponding one ofthe one or more impactor arms, the lever cap being arranged for slidingon a shaft which extends towards the proximal cap, wherein proximalmovement of the lever cap towards the proximal cap causes the one ormore lever arms to deform and to push against the one or more impactorarms and to cause the one or more impactor arms to deform.

In accordance with a non-limiting embodiment of the invention each ofthe one or more lever arms is formed with a pivot.

In accordance with a non-limiting embodiment of the invention each ofthe one or more impactor arms includes an arm member formed with apivot.

In accordance with a non-limiting embodiment of the invention a limiteris coupled to a (e.g., distal) portion of the one or more impactor arms,the limiter controlling an amount of radially-outward expansion ofdistal portions of the one or more impactor arms.

In accordance with a non-limiting embodiment of the invention when theone or more impactor arms deform by the proximal movement of the levercap towards the proximal cap, distal portions of the one or moreimpactor arms do not expand radially outwards.

In accordance with a non-limiting embodiment of the invention thestabilizer includes mating structure for engagement with the impactor.

In accordance with a non-limiting embodiment of the invention the matingstructure includes registration lugs that protrude proximally from aproximal end piece of the stabilizer, the registration lugs beingarranged to move into grooves formed in the one or more lever arms.

In accordance with a non-limiting embodiment of the invention each ofthe one or more impactor arms includes struts which meet at a roundedjunction.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood and appreciated more fully fromthe following detailed description, taken in conjunction with thedrawings in which:

FIG. 1 is a simplified pictorial illustration of a stabilizer and animpactor, delivered over a guidewire, in accordance with a non-limitingembodiment of the invention;

FIG. 2 is a simplified pictorial illustration of the impactor positionedover leaflets of a valve, such as the aortic valve, in which case thestabilizer has first been delivered in a retrograde delivery through theascending aorta into the aortic root and through the aortic annulus intothe left ventricle, and the impactor has been delivered over the sameguidewire through the ascending aorta into the aortic root, so that thestabilizer is inferior to the leaflets and the impactor is superior tothe leaflets;

FIG. 3 is a simplified pictorial illustration of moving the stabilizerand the impactor towards each other, the leaflets being sandwichedbetween the stabilizer and the impactor;

FIG. 4 is a simplified pictorial illustration of expanding thestabilizer which acts to deploy the impactor arms of the impactor;

FIGS. 5A and 5B are simplified pictorial illustrations of the impactor,respectively, before and after expansion (that is, respectively incontracted and expanded orientations);

FIG. 6 is a simplified pictorial illustration of the stabilizer, showingmating structure for engagement with the impactor;

FIGS. 7A and 7B are simplified enlarged illustrations of engagement ofthe stabilizer with the impactor, showing how the mating structureregisters the stabilizer with respect to the impactor; and

FIG. 8 is a simplified enlarged illustration of structure of theimpactor arms of the impactor, in one non-limiting embodiment of theinvention.

DETAILED DESCRIPTION OF EMBODIMENTS

First an overall description of the stabilizer and impactor of theinvention and one possible delivery are described with reference toFIGS. 1-4. A more detailed description of the stabilizer and impactorthen follows with reference to FIGS. 5A-6.

Reference is now made to FIGS. 1-4, which illustrates a stabilizer 10and an impactor 12, which may be delivered over a guidewire 14 (such aswith a delivery catheter, not shown), in accordance with a non-limitingembodiment of the invention.

Guidewire 14 is first moved through a blood vessel, such as a peripheralartery, using a retrograde approach, through the aortic arch and intothe ascending aorta, and then through the aortic valve into the leftventricle. The delivery catheter is then moved over the guidewire 14 anddelivers stabilizer 10 through the ascending aorta into the aortic rootand through the aortic annulus into the left ventricle, inferior to theaortic valve. The impactor 12 may be delivered over the same guidewire14 through the ascending aorta and then through the sinotubular junctioninto the Valsalva sinuses of the aortic root, just above the cusps ofthe aortic valve, so that the impactor 12 is superior to the leafletsand the stabilizer 10 is inferior to the leaflets (the positions inFIGS. 2-4).

In FIG. 3, the stabilizer 10 and impactor 12 are moved towards eachother. For example, stabilizer 10 may be moved proximally towardsimpactor 12; impactor 12 may be moved distally towards stabilizer 10; orstabilizer 10 may be moved proximally towards impactor 12 and impactor12 may be moved distally towards stabilizer 10. In all cases, theleaflets are sandwiched between stabilizer 10 and impactor 12.

In FIG. 4, stabilizer 10 is expanded, which acts to deploy impactor armsof impactor 12. The movement of stabilizer 10 and impactor 12 towardseach other fractures leaflet calcifications. After fracturing leafletcalcifications, the stabilizer 10 and impactor 12 may be removed bymoving them proximally over guidewire 14 and then removing guidewire 14.

Reference is now made to FIGS. 5A and 5B, which illustrate the impactor12, in accordance with a non-limiting embodiment of the invention.

Impactor 12 includes one or more impactor arms 16. In the illustratedembodiment there are three impactor arms 16, which are suitable for atricuspid valve, but the invention may be carried out with other numbersof arms. Each arm 16 may be constructed of two struts 18 which meet at ajunction 20, such as a rounded end cap, which may be secured to thestruts 18, such as but not limited to, by welding, brazing, bonding orother joining techniques, or may be one piece with the struts. Theroundness of junction 20 may help prevent piercing tissue duringoperation of the device.

Each strut 18 may include a slender member, such as but not limited to,a wire, rod, strip, thin beam and the like, coupled to an arm member 22.Arm member 22 extends from the proximal end of strut 18 to a proximalcap 24, and is formed with a pivot 26 intermediate the proximal end ofstrut 18 and the proximal cap 24. Pivot 26 may be a score line, thinnerportion, weakened portion and the like, which enables arm member 24 tobend or buckle when being expanded from the contracted orientation tothe expanded orientation. FIG. 8 illustrates one possible structure ofpivot 26, in which the proximal portion of the arm member 22 has athinner portion which serves as pivot 26, and terminates in a flap 27which is welded or otherwise joined to the distal portion of arm member22. Of course, the arm member 22 may be a one-piece construction orother constructions. It is noted that arm member 22 may be of sufficientlength and stiffness to that it itself is the strut (and ends atjunction 20) and there is no need to couple a strut to the arm member.

Impactor 12 includes one or more lever arms 28. In the illustratedembodiment there are three lever arms 28, but the invention may becarried out with other numbers of lever arms; there is preferably aone-to-one correspondence of lever arms 28 to arm members 22. The distalends of the lever arms 28 may be coupled to a lever cap 30 and each ofthe proximal ends of the lever arms 28 may be coupled to a proximalportion of a corresponding arm member 22. Each lever arm 28 is formedwith a pivot 32 intermediate the proximal and distal ends of lever arm28. Pivot 32 may be a score line, thinner portion, weakened portion andthe like, which enables lever arm 28 to bend or buckle during expansion.Lever cap 30 may be arranged for sliding on a shaft 34 (which may betelescoping) which extends towards proximal cap 24 (either reaching ornot reaching proximal cap 24). It is noted that the impactor arms 16 andthe lever arms 28 may deform (without limitation, bend, bow or buckle,etc.) outwards even without pivots, due to their elasticity orflexibility. The pivots may help define the place where they bend, bowor buckle.

A limiter 36 may be coupled to a (e.g., distal) portion of arm members22, such as by being assembled in mounting holes or any other suitablemethod. The limiter 36, as well as any other part of the device (bothimpactor and stabilizer) may be made from nitinol or stainless steel orany other suitable material.

FIG. 5A illustrates impactor 12 in the contracted orientation. In orderto expand impactor arms 16 to the expanded orientation of FIG. 5B, levercap 30 is moved proximally towards proximal cap 24, which causes leverarms 28 to deform, e.g., bend or buckle radially outwards at pivots 32.The outward movement of the proximal portions of lever arms 28 pushesthe proximal portions of arm members 22 outwards and proximally (upwardsin the sense of FIGS. 5A and 5B), and the arm members 22 deform, e.g.,bend or buckle at pivot 26. Although in one embodiment the distalportions of arm members 22 may expand radially outwards, in thepreferred embodiment the distal portions of arm members 22 do not expandradially outwards but rather either remain at approximately the sameradial position or contract radially inwards. The amount ofradially-outward expansion of the distal portions of arm members 22 iscontrolled by the limiter 36. Limiter 36 may be formed with anintermediate bend 38, which stretches and straightens when impactor arms16 are expanded.

Reference is now made to FIG. 6, which illustrates the stabilizer 10.Stabilizer 10 may be formed with a plurality of flexible members 40,which may form a web, mesh truss or similar structure, which can beexpanded outwards. The distal ends of flexible members 40 may be coupledto a distal end piece 42 and the proximal ends of flexible members 40may be coupled to a proximal end piece 44. Stabilizer 10 may be formedwith a plurality of registration lugs 46, such as resilient fingers thatprotrude proximally from proximal end piece 44. The proximal end piece44 and the registration lugs 46 together form mating structure forengagement with the impactor 12, as is now explained with reference tothe enlarged views of FIGS. 7A and 7B.

In FIG. 7A, stabilizer 10 and impactor 12 have been moved towards eachother. The registration lugs 46 that protrude proximally from proximalend piece 44 pass through an inner radial gap in lever cap 30 of leverarms 28 and are received in grooves 48 formed in the distal portions oflever arms 28. The groove 48 may be any kind of cutout, either throughthe entire thickness of the lever arm or not through the entirethickness (i.e., blind), such as but not limited to, a notch, aperture,depression, channel and the like.

The stabilizer 10 (via the engagement of registration lugs 46 with levercap 30) causes lever cap 30 to move proximally towards proximal cap 24,which causes lever arms 28 to bend or buckle radially outwards andpushes the proximal portions of arm members 22 outwards and proximally.Arm members 22 bend or buckle at pivot 26. The impactor 12 is now readyto fracture calcifications in the leaflets.

The registration lugs 46 and the grooves 48 may self-align, that is, theregistration lugs 46 may circumferentially rotate somewhat as they slideinto grooves 48. The registration of registration lugs 46 with grooves48 may help achieve proper registration of the impactor arms 16 with theleaflets of the valve so that the impactor arms 16 are properlypositioned over the calcifications in order to fracture them.

The term “fracture” refers to any kind of reduction in size or anymodification in shape or form, such as but not limited to, fracturing,pulverizing, scoring, breaking, grinding, chopping and the like.

What is claimed is:
 1. A device for fracturing calcifications in heart valves comprising: a stabilizer and an impactor movable towards each other, said impactor comprising one or more impactor arms, each of which extends distally from a proximal cap; said impactor further comprising one or more lever arms each of which is distally coupled to a lever cap and proximally coupled to a corresponding one of said one or more impactor arms, said lever cap being arranged for sliding on a shaft which extends towards said proximal cap, wherein proximal movement of said lever cap towards said proximal cap causes said one or more lever arms to deform and to push against said one or more impactor arms and to cause said one or more impactor arms to deform.
 2. The device according to claim 1, wherein each of said one or more lever arms is formed with a pivot.
 3. The device according to claim 1, wherein each of said one or more impactor arms comprises an arm member formed with a pivot.
 4. The device according to claim 1, further comprising a limiter coupled to a portion of said one or more impactor arms, said limiter controlling an amount of radially-outward expansion of distal portions of said one or more impactor arms.
 5. The device according to claim 1, wherein when said one or more impactor arms deform by the proximal movement of said lever cap towards said proximal cap, distal portions of said one or more impactor arms do not expand radially outwards.
 6. The device according to claim 1, wherein said stabilizer comprises mating structure for engagement with said impactor.
 7. The device according to claim 1, wherein said mating structure comprises registration lugs that protrude proximally from a proximal end piece of said stabilizer, said registration lugs being arranged to move into grooves formed in said one or more lever arms.
 8. The device according to claim 1, wherein each of said one or more impactor arms comprises struts which meet at a rounded junction. 